Method and Apparatus for Identifying Unused RF Channels

ABSTRACT

A wireless connection apparatus which scans radio frequency bands for local quiet unused, vacant, or unassigned frequencies which the apparatus can use, on a temporary basis, to establish a link for communicating between a portable multimedia device and a nearby RBDS/RDS configured receiver or source. The apparatus does not interfere with or utilize frequencies actively in use by an assigned user.

FIELD OF INVENTION

The present invention relates generally to the operating protocol forportable multimedia devices such as cell phones, multimedia players,personal digital devices, and the like. More specifically, the inventionrelates to the protocol for sending data between a multimedia player anda nearby receiver, and even more specifically for determining theoperating frequencies for such communications links.

DESCRIPTION OF RELATED ART

The field of consumer electronics is expanding at a rapid rate, offeringsmall, programmable digital communications and digital devices capableof reproducing music, displaying images, and performing multiplenumerical data management tasks. These devices are interactive with oneor more sources of, or play-back devices for analog or digital: music,images, text, or numerical data (herein collectively referred to as“data” for convenience, and not intended to limit in any way the natureof the data content). Generally, the portable multimedia devices receivedata from a source, but may also transmit data to a nearby receiver.Typical currently appropriate receivers incorporate the European RadioData System (RDS) or the United States Radio Broadcast Data System(RBDS) standards, or both. The portable multimedia devices transmit orreceive either via a hardwire connection or wirelessly on a specificassigned frequency or within a designated frequency band, sharing thefrequency and accompanying separation frequencies with an activeassigned user. The plethora of available portable multimedia devices andthe physical limitations of the available radio frequency bandsinexorably leads to interference between portable devices and/or betweenportable devices and other frequency users.

Throughout the world, 87.5-108 MHz, or some portion thereof, is used asa Frequency Modulated (FM) broadcast band, with one exception; Japanuses a 76-90 MHz band. Users are allocated a channel within the band,typically with 0.1 MHz channel spacing. The assigned nominal centerfrequency of an FM broadcast station is usually an exact multiple of 100kHz, however, individual countries may assign other nominal centerfrequencies (e.g. Italy uses multiples of 50 MHz). The bandwidth of atypical FM transmission is normally somewhat wider than these figures,and depends, in part, on whether stereo is used and the manner in whichthe peak deviation is regulated. Individual countries may specify othernominal band widths. Within the assigned bandwidth, subcarrierfrequencies are used to carry information piggy-backed on the FMstation's carrier signal. These subcarriers are the basis of the RFtransmission system, allowing for the transmission of information suchas station or subject matter identification, emergency alerts, etc.

What is needed is a way to increase the available frequencies forportable multimedia devices to use more efficiently for short rangecommunications with data sources and FM play-back devices.

SUMMARY OF THE INVENTION

Accordingly, the present invention is a portable multimedia devicewireless connection apparatus which scans the commercial FM band forlocal unused, vacant, quiet or unassigned frequencies or clear channelswhich the apparatus can use, on a temporary basis, to establish a linkfor communicating between the portable multimedia device and a nearby FMradio receiver or other source. The scanner identifies frequencies withsignificantly lower signal strength than adjacent frequencies, oralternatively, identifies frequencies having a signal strength below apreset threshold that represents, for instance, the minimum acceptablesignal level for any particular receiver. For convenience only, suchfrequencies, including the term clear channel, are herein referred to as“quiet” frequencies. The apparatus does not interfere with or utilizefrequencies actively in use by an assigned user.

The apparatus (hereinafter referred to as a “scanner” for convenienceand is not intended to limit in any way the function of the apparatus)is a low power FM transmitter configured to connect to a portablemultimedia device which may be, for example an MP3 player or an iPod™,and contains circuitry to communicate with the portable multimediadevice in both a receive and transmit mode. The operator manuallydirects the scanner to look for the most quiet frequency for use. Thescanner searches the broadcast FM band for any inactive FM carrierfrequency within a limited local range and selects a quiet frequency foruse as a temporary connection between the portable multimedia device anda receiver. The scanner then establishes on that frequency an FM linkbetween the portable multimedia device and the receiver for playback ofdata from the portable multimedia device through the receiver. In analternative embodiment, the scanner will continue to monitor thefrequency in use to detect any signal from an assigned user or excessivenoise. If a signal or excessive noise is detected, the scanner willautomatically transfer the connection between the portable multimediadevice and the receiver to a different quiet frequency. The scanner willoperate with a mobile receiver such as in an automobile or a portableradio (boom box) and in a fixed environment such as a home or officeover an appropriately configured radio or television receiver.

The scanner may also serve as a connection between a data source and aportable multimedia device if appropriately configured. It may bespecialized to function with one or more type or brand of portablemultimedia device. It may further contain circuitry that will power theportable multimedia device and/or recharge the portable multimediadevice batteries while facilitating playback from the portablemultimedia device to a receiver, in the absence of data transfer forplayback, or while the portable multimedia device is not otherwiseoperating.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the below referenced accompanying Drawing. Reference numbers refer tothe same or equivalent parts of the present invention throughout theseveral figures of the Drawing.

FIG. 1 is a block diagram showing the components of an exemplarywireless connection apparatus in accordance with the present invention.

FIG. 2 is a schematic diagram of an exemplary main circuit board for theapparatus of FIG. 1.

FIG. 3 is a schematic diagram of an exemplary connector circuit boardfor the apparatus of FIG. 1.

FIG. 4 is a schematic diagram of an exemplary scanner circuit for theapparatus of FIG. 1.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

The following description of the exemplary embodiment refers to aspecific radio frequency band (the FM band). Other radio frequenciescould be used in other embodiments. Discussion of a specific frequencyrange is not intended to limit the invention to such range. Referringnow to FIG. 1, the components of an exemplary system for using thepresent scanner is shown in block diagram. Portable multimedia device 10may be any appropriate digital data device such as an MP3 player, agame, a pager, an iPod™, or a Personal Data Assistant or cell phone, forexample. Heretofore new portable multimedia devices not yet availablemay be supported by an embodiment using the principles of the presentinvention, and are contemplated by, and included in, the presentinvention. Portable multimedia device 10 is connected to scanner 20 bycommunications link 15 which may be either hardwire (a direct wireconnection) or wireless. A hardwire connection would require anappropriate physical connector for the specific device 10. The connectormay, for example, take the form of an electrical connector (e.g. a plugor socket), a cradle or holder, or a docking station, separately or incombination, and may also include some means to temporarily orpermanently attach the connection to a vehicle or some other object.Further, an embodiment is contemplated with an electrical connectoradapted to connect with a variety of cradles, holders, docking stations,and the like, to work with a variety of portable multimedia devices. Forexample, a multipin connector in which different pin combinationselectrically connect with different devices.

Power adapter 50 is connected to scanner 20 via connection 55 which istypically hardwired. Connection 55 may alternatively be incorporatedinto scanner 20, forming a single integrated unit. Power adapter 50connection 55 is preferably configured to plug into a vehicle powerreceptacle, but may also be configured to connect to a battery internalto scanner 20, an external battery pack having one or more batteries, agenerator (for example a hand cranked emergency generator), or a typicalhousehold utility 120 vac power source. Scanner 20 may have appropriatecircuits, indicators and switches to accommodate a variety of powersources.

Scanner 20 typically is a conveniently-sized housing that containscircuits such as shown in FIG. 2 and FIG. 3 to convey digital databetween portable multimedia device 10 and receiver 90 overcommunications links 15 and 95. Communication link 95 is preferably alow powered FM band frequency wireless link. Should other frequencybands be made available for public use, link 95 may be over a frequencyin such a band. Similarly, link 95 may be over any public radiofrequency available in any country, as allowed by law. Receiver 90typically is an RBDS/RDS configured radio but may be any otherappropriately configured device (e.g. a television set). Alternatively,receiver 90 may be a data source, such as a computer, audio player, or avideo player for data transfer to portable multimedia device 10 throughscanner 20. Scanner 20 may be specialized for one or more type, brand ormodel of portable multimedia device. Scanner 20 has indicators andcontrols available for an operator to select functions appropriate tothe desired operations. In the exemplary embodiment, such controlsinclude a manual control to initiate the band frequency scan mode.Alternative embodiments include computer-activated controls whichinitiate scans at designated intervals or events (e.g. noise levelsexceed a standard, geographic changes of the receiver as in a movingvehicle, etc.).

Referring now to FIG. 3 and FIG. 4, when the autoscan feature isinitiated by the operator, the microprocessor (U1, FIG. 3) switches theFM transmitter to sequentially scan frequencies through the available RFband width. The microprocessor U1 then engages the scanner circuit (FIG.4) to monitor the RF level at each frequency in the band. Themicroprocessor U1 uses a form of heterodyne conversion to downconvertthe RF to baseband. As shown in FIG. 4, the RF is received through the“ANT” connection, coupled to the mixer (D2, D3, D4), amplified via Q3,low pass filtered by L13 and C43 and C26, further amplified through U4A,U4D and U4C, and finally converted into a DC level via D7. This level isfed to the microprocessor (U1, FIG. 3), which stores the levelinformation. The microprocessor U1 scans through the broadcast band,recording the level at each frequency. It then determines the lowestsignal, and reports that frequency back to the user as the desiredchannel for setting the transmitter and associated receiver.

In a second embodiment, scanner 20 monitors the commercial FM frequencyband for frequencies that are not in current use in the area wherescanner 20 is operating. Upon identifying a quiet frequency, scanner 20automatically establishes link 95 to connect portable multimedia device10 to receiver 90. Link 95 is low powered and does not interfere withother users beyond a range of approximately 50 meters. If an outsidesignal or excessive noise on link 95 frequency is detected by scanner20, the operator may command another scan and select cycle, or in analternative embodiment, scanner 20 automatically switches link 95frequency to a different quiet frequency for continuing communicationsbetween portable multimedia device 10 and receiver 90. Additionalcapabilities of scanner 20 may include identifying more than one quietfrequency and automatically configuring one or more preset controls tothe identified frequency. Scanner 20 may scan the entire FM broadcastband, or alternatively, be provided with a computer capability thatdirects it to skip selected channels. That capability could include adatabase of probable unused frequencies.

While the present invention has been described in terms of a preferredembodiment, alternate circuits that perform the same function of scanner20 are possible. Therefore, the invention should be interpreted asincluding all equivalents, alterations and permutations that perform thebasic function of monitoring for, selecting, and automaticallyestablishing communications over vacant radio frequencies.

Information as herein shown and described in detail is fully capable ofattaining the above-described object of the invention, the presentlypreferred embodiment of the invention, and is, thus, representative ofthe subject matter which is broadly contemplated by the presentinvention. The scope of the present invention fully encompasses otherembodiments which may become obvious to those skilled in the art, and isto be limited, accordingly, by nothing other than the appended claims,wherein reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore.”

All structural and functional equivalents to the elements of theabove-described preferred embodiment and additional embodiments that areknown to those of ordinary skill in the art are hereby expresslyincorporated by reference and are intended to be encompassed by thepresent claims. However, it should be readily apparent to those ofordinary skill in the art that various changes and modifications inform, apparatus material, and fabrication material detail may be madewithout departing from the spirit and scope of the invention as setforth in the appended claims.

Moreover, no requirement exists for a device or method to address eachand every problem sought to be resolved by the present invention, forsuch to be encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. No claim herein is tobe construed under the provisions of 35 U.S.C. 112, sixth paragraph,unless the element is expressly recited using the phrase “means for.”

INDUSTRIAL APPLICABILITY

The present invention applies industrially to consumer electronicdevices. More particularly, the present invention applies industriallyto individually portable multimedia devices available to the public.Even more particularly, the present invention applies to hand-heldelectronic devices for receiving and playback of digital audio, visualand numerical data and the means to interface such portable multimediaelectronic devises to an appropriately configured radio or other device.

1. An apparatus for connecting a portable multimedia device to a receiver for data play-back, comprising: first coupling means for coupling the apparatus to a portable multimedia device; scanner means for scanning radio frequencies for a quiet carrier frequency and, upon detection of a quiet carrier frequency, indicating the detected quiet carrier frequency; mid transmitter means for transmitting data to be carried over the detected quiet carrier frequency from the portable multimedia device to the receiver and said apparatus being connected with a source of electric power selected from the group consisting of a vehicle power receptacle, a battery, a battery pack, a generator, and a commercial electric outlet.
 2. An apparatus as in claim 1 wherein the scanned radio frequencies are in the FM bandwidth.
 3. An apparatus as in claim 1 wherein the first coupling means is selected from the group consisting of a wireless connection and a hardwire connection.
 4. (canceled)
 5. An apparatus as in claim 1, wherein the portable multimedia device has an internal power supply, further having means for recharging the portable multimedia device power supply.
 6. An apparatus as in claim 1 further having means for conveying data from a source to the portable multimedia device.
 7. An apparatus as in claim 6 further including power means for powering the portable multimedia device and means for recharging the portable multimedia device power supply.
 8. An apparatus as in claim 7 wherein the radio frequency scanner monitors the selected quiet frequency for the presence of a signal or excessive noise and automatically switches to another quiet frequency upon detection of said signal or noise.
 9. An apparatus for connecting a portable multimedia device to a receiver for data play-back, comprising: a connection between the portable multimedia device and a radio frequency scanner for detecting a quiet radio carrier frequency and for automatically wirelessly coupling the portable multimedia device to the receiver upon detection of a quiet carrier frequency; data transfer means for conveying data from the portable multimedia device to the receiver; power means for providing power to the apparatus and the portable multimedia device and means for conveying data from a source to the portable multimedia device.
 10. An apparatus as in claim 9 wherein the connection between the apparatus and the portable multimedia device is a hardwire connection and wherein the hardwire connection further comprises a physical connector selected from at least one of the group consisting of an electrical plug, an electrical socket, a cradle, a holder, and a docking station.
 11. (canceled)
 12. An apparatus as in claim 9 wherein the power means is selected from the group consisting of a vehicle power outlet, a battery, a battery pack, a generator, and a utility outlet.
 13. An apparatus as in claim 12 further having means for recharging the portable multimedia device power supply from the power means; and wherein the connection between the portable multimedia device and the radio frequency scanner is a hardwire connection having a physical connector selected from at least one of the group consisting of an electrical plug, an electrical socket, a cradle, a holder, and a docking station.
 14. A apparatus as in claim 9 wherein the radio frequency scanner monitors the selected quiet carrier frequency for the presence of a signal or excessive noise and automatically switches to another quiet carrier frequency upon detection of said signal or noise.
 15. A method for transmitting data play-back from a portable multimedia device to a receiver comprising the steps of: scanning a radio frequency band for a quiet frequency; identifying a detected quiet frequency; setting the receiver to the indicated quiet carrier frequency; wirelessly transmitting data from the portable multimedia device to the receiver and providing at least one powering means selected from the group of means for recharging the portable multimedia device power supply and for providing operating power for the portable multimedia device.
 16. A method as in claim 15 wherein connecting the portable multimedia device to the scanning means is by providing a hardwire connection wherein the hardwire connection has a physical connector selected from at least one of the group consisting of an electrical plug, an electrical socket, a cradle, a holder, and a docking station.
 17. A method as in claim 15 wherein scanning radio frequencies includes scanning the FM radio frequency band.
 18. A method as in claim 15 further providing data transmitting means for transmitting digital data from a source to the portable multimedia device.
 19. (canceled)
 20. A method as in claim 15 wherein the scanning means continues to monitor the quiet frequency for a signal or noise and upon detection of said signal or noise automatically switches the wireless connection to another quiet frequency. 